Not Applicable.
This invention relates to metal fasteners, specifically to metal fasteners that are used to bond flooring materials together.
Traditionally, when cast-in-place concrete was used with a wood floor in non-residential construction, the structure was often designed as a composite construction to reduce the size of the members. In this type of construction both materials (concrete and wood) were designed to act in unison due to the bond between them. Composite action was generally achieved between the concrete slab and the supporting wood beams independent of the wood sheathing between the beams. This action was typically accomplished with some form of xe2x80x9cshear studsxe2x80x9d such as nails, steel rods, metal plates bolts, pipes, and the like. The shear studs engaged both materials and acted to resist the sliding of the slab with respect to the beams when the unit was deformed under the influence of a load. Wire mesh and reinforcement bars were generally embedded in the wet concrete to impart strength in resisting bending, cracking, and puncture stresses.
In light frame residential construction the process of casting concrete onto wood floors was generally done without the task of attaching some type of shear studs to the floor joists. Concrete was simply poured onto pre-positioned metal reinforcement placed on the floor sheathing and screeded to a depth that provided cover for the steel reinforcementxe2x80x94usually 1.5xe2x80x3 to 3xe2x80x3. Pouring seamless floors were avoided because of the cracking that resulted from shrinkage as the concrete cured. Cracking was controlled by the use of expansion and control joints but often these joints filled with dirt and over time took away from the appearance of the floors.
Concrete was a very heavy material and the added weight to a residential floor was considerable. Often a concrete slab added as much as 30 to 40 lb. per sq. ft. of dead load. Most residential floors were designed to carry only 10 to 15 lb. per sq. ft. of dead load. Thus, many contractors and homeowners were reluctant to spend the extra money to build or add the necessary supporting structure to carry the extra weight. Concrete was also a very brittle material that cracked easily under small deflections. Such deflections were common in light frame residential construction and became more so as the structure aged and the wood members shrank.
Whatever flooring system is evolved in residential construction to utilize concrete""s beneficial properties (fire resistance; freedom from allergies; low maintenance; colorability; low installed costs, etc.) must out of necessity reduce the weight of the concrete floor so no additional support is required and, eliminate the inherent cracking caused from shrinkage and deflection of the concrete.
Thereafter, inventors created several types of concrete floor and wood constructions in which shear resisting elements were used to achieve composite action. U.S. Pat. No. 4,841,703 to Grimaud (1989) discloses a complex assembly of parts which appear to produce a concrete and wood floor composite using a metal tube as a shear resistor. However, these tubes only resist shear at the points they are driven into the wood beam. The sheathing material between the beams lacks any composite action with other materials and as the inventor states, xe2x80x9ccan be removedxe2x80x9d. In an article by Godychi et al entitled xe2x80x9cVerbunddecke aus Holzrippen unde Beton-plattexe2x80x9d (Bauinggenieur 59 (1984) 477-483, Springer-Verlag, West Germany, describes a concrete floor in which steel nails are partially driven into the wood joists leaving the upper part of the nails and heads to engage the concrete floor. While these nails were confined only to the beams and not to the sheathing, they suffer from bending in their middle and bottom lengths that would be produced by the effects of the horizontal shear forces mentioned above.
In another floor, sheet metal connector plates with integral connecting teeth were attached to both sides of the wood beam. The top portion of each plate projected above the beam and was cut to form a series of pointed connection teeth which pass through the floor sheathing when the latter is put into place between the beams. These teeth subsequently become embedded into the concrete slab. One such floor is mentioned without being described in detail in European patent EPAL-0104629 Poutanen, Tuomo Tapini). While this floor had a advantage over those previously mentioned in that the connection is very rigid in resisting the horizontal shear stresses mentioned above, it does suffer from the following drawbacks:
(1) The attachment of the plates to the vertical sides of the beam would require a press to be used which must be capable of exerting considerable force. If this process was performed off-site, storage and handling of these beams would become difficult because of the poor stiffness of the connection teeth and the plates in the transverse direction. If the process was performed on-site, bringing such a large press into contact with the beams would be very difficult.
(2) Piercing the wood sheathing with connecting teeth from the metal plates would prove to be hard to do. Furthermore, if the sheathing was anchored to the floor beams first, then the sheathing would prevent the upper part of the plates from engaging the concrete.
In accordance with the present invention a metal fastener comprising a flat plate, projecting teeth punched therefrom and bent at right angles to the top side of the plate for engaging concrete, and means for anchoring said plate to a floor substrate.
Accordingly, besides the objects and advantages of the metal fastener described in my above patent, several objects and advantages of the patent are:
(a) to provide a fastener that can uniformly provide composite action over the entire floor between the concrete and wood without regard to the location of the supporting floor joists;
(b) to provide a fastener that will eliminate floor cracking;
(c) to provide a floor fastener that can rapidly be attached to a penetrable floor substrate by unskilled workmen;
(d) to provide a fastener that would allow the surface of the concrete to be colored or stained and later stamped with various patterns and textures of the user""s choice.
(e) to provide a fastener whose use will allow a thin layer of concrete to be placed on a new or existing floor that does not require extra structural support;
(f) to provide a fastener that will allow a fire rated floor assembly to be produced which will protect occupants of the building against smoke and fire;
(g) to provide a fastener that will produce beautiful low cost floors that will have wide acceptance in all sectors of residential and commercial construction;
(h) to provide a fastener that will allow radiant heating elements to be installed onto the floor substrate and then covered with a seamless concrete floor to provide heating for the home;
(i) to provide a fastener that will produce seamless, crack free floors without the need for expansion joints and control joints.
Further objects and advantages are to provide a fastener which can be used to produce thin concrete floors for use outside of buildings to cover existing and new floors of balconies, roofs, decks, terraces, patios, and the like, to produce attractive, long wearing, low maintenance flooring that can be supported without additional structural costs. Still further objects and advantages will become apparent from the consideration of the ensuing description and drawings.